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研究了大田生长条件下两系超高产杂交水稻(Oryza sativa L.)“两优培九”和我国大面积推广的三系杂交水稻“汕优63”从灌浆期到收获期剑叶PSⅡ光化学特性和Rubisco大、小亚基含量的变化。结果表明:可溶性蛋白质和叶绿素含量随剑叶生长时间的延长先缓慢下降,后期有一个快速降解的过程,“汕优63”降解的速率高于“两优培九”;Fv/Fm和qP都呈下降的趋势,qN则是先降然后上升。激发压(1-qP)在前期的变化较为平稳,后期则急剧增加,“汕优63”较“两优培九”增加快。Rubisco大、小亚基的含量与叶绿素、可溶性蛋白含量一样在前期下降比较慢,后期也有一个快速降解的过程,“汕优63”比“两优培九”降解快。激发压的增加与Rubisco大、小亚基的降解呈显著的线性相关性。我们推测PSⅡ激发压的急剧增加可能诱发了水稻剑叶的快速衰老过程。“两优培九”高产的重要生理原因之一,可能是它比“汕优63”有更强的光合能力并能维持更持久和较高的光合功能期。
The photochemical characteristics of PS Ⅱ in flag leaves of two-line super high-yielding hybrid rice (Oryza sativa L.) and the large-scale three-line hybrid rice “Shanyou 63” , Small subunit content changes. The results showed that the content of soluble protein and chlorophyll decreased slowly with the extension of the growth time of flag leaves, and the latter had a rapid degradation process. The rate of degradation of “Shanyou 63” was higher than that of “Liangyoupeijiu”; Fv / Fm and qP decreased Trend, qN is the first drop and then rise. The excitation pressure (1-qP) changed more smoothly in the early stage and sharply increased in the late stage. The “Shanyou 63” increased more rapidly than the “Liangyoupeiju”. The contents of Rubisco big and small subunits decreased with the content of chlorophyll and soluble protein in the early stage, but also decreased rapidly in the later stage. The “Shanyou 63” degraded faster than the “Liangyoupeiju”. There was a significant linear correlation between the increase of excitation pressure and the degradation of Rubisco large and small subunits. We speculate that the rapid increase of PSⅡ-induced pressure may induce the rapid senescence of rice flag leaf. One of the most important physiological reasons for the high yield of “Liangyoupeijiu” may be that it has stronger photosynthetic capacity than Shanyou 63 and can maintain more long-lasting and higher photosynthetic function.